.toTop {
  position: fixed;
  right: 70px;
  bottom: 70px;
  height: 42px;
  text-align: center;
  width: 42px;
  cursor: pointer;
  background: #9F9F9F url("../images/back-top.png") no-repeat center center;
  span {
    display: block;
    width: 26px;
    height: 26px;
    padding: 8px;
    line-height: 13px;
    font-size: 12px;
    color: #FFF;
    background-color: #767676;
    opacity: 0;
    transition: opacity .2s;
  }
  &:hover {
    background-image: none;
    span {
      opacity: 1;
    }
  }
}
